Remove door card.
remove 2 screws inside on rear of handle.
remove screws on door lock mech.
pull door handle towards front of car be firm but carefull.
once handle is out there is a clip half way up the body to push in then pull the lock out.
1 - Back of the door you will see the lock box.
2 - Release 2 screws from lock box.
3 - Removing rear lock box from back plate
4 - You will see the locks back plate.
5 - Black plate you will see a thin bar with grooves across its width.
6 - Unscrew these screws and put them with the lock box screws.
7 - Take a new barrel & lay it alongside the one you have just taken out.
8 - Compare old to new barrel and cut off shank of new lock to the same length as the old one